1. Field of the Invention
The present invention relates to an ink jet recording apparatus for performing recording by discharging ink from recording means to a recording material, and relates to a recovery mechanism portion of the recording apparatus.
2. Description of Related Art
A recording apparatus having a function of a printer, a copying machine, a facsimile or the like, or a recording apparatus, which is used as output equipment of a compound type electronic instrument or work station including a computer, a word processor and the like, is configured to record images (including letters, marks and the like) on recording materials (recording media), such as paper, cloth, plastic sheets, sheets for an overhead projector (OHP), or the like, on the basis of recording information. In a serial type recording apparatus, which performs recording while executing main scanning in a direction crossing with the conveyance direction of a recording medium, images are recorded with a recording head (recording means) mounted on a carriage moving along the recording medium. Having finished recording of one line, the serial type recording apparatus performs paper feeding for a predetermined pitch. After the paper feeding, the serial type recording apparatus executes the recording of the images of the next line on the recording material, which has stopped again after the paper feeding. The serial type recording apparatus performs the recording on the whole recording medium by repeating the above-mentioned recording operation. On the other hand, in a line type recording apparatus, which performs recording only in the conveyance direction of a recording material, the recording material is set at a predetermined position, and the recording of a line is performed at once. After that, paper feeding for a predetermined pitch is performed, and the recording of the next line is performed at one time. The line type recording apparatus repeats the above-mentioned recording operation to perform the recording on the whole recording material.
Among the above-mentioned recording apparatuses, an ink jet recording apparatus, which performs recording by discharging ink from a recording head to a recording material, can easily miniaturize recording means, and can record highly fine images at a high speed. Furthermore, the ink jet recording apparatus can perform recording on a sheet of plain paper without special processing. Moreover, the running cost of the ink jet recording apparatus is inexpensive, and the noise of the ink jet recording apparatus is minimal since the ink jet recording apparatus adopts a nonimpact system. Besides, the ink jet recording apparatus can easily record color images by the use of many kinds of inks (for example, color inks). The ink jet recording apparatus has the advantages described above. Moreover, demands for the quality of the recording materials used in the ink jet recording apparatus are various, and recently development meeting these demands has made progress. In addition to ordinary recording paper, a resin thin plate (for an OHP and the like), cloth, leather, nonwoven fabric, metal and the like has begun to be used.
In the ink jet recording apparatus, recording is performed by discharging ink from fine discharge ports. Consequently, when ink is increased in viscosity or dried due to evaporation of liquid ink components (evaporation of a solvent) in the vicinity of the discharge ports, or when ink or dust such as paper powder is attached to a discharge port surface, or further when bubbles intrude into ink in the discharge ports, not only discharging of the ink becomes unstable, but also faulty discharges of ink, undischarged states of ink and the like are sometimes produced.
Accordingly, a recovery mechanism portion for maintaining and recovering the ink discharge performance of a recording head as recording means in a good state is provided. As recovery means in the recovery mechanism portion, there are wiping means, capping means, suction means and the like. The wiping means wipes an discharge port surface to clean it (wiping cleaning) by sliding a wiper made of an elastic member such as rubber or the like on the discharge port surface to rub the discharge port surface for cleaning the discharge port surface by removing unnecessary ink attached to the ink discharge port surface due to ink mist or ink drops rebounded from a recording material and foreign matter such as paper powder attached to the ink discharge port surface during recording operations.
When ink has not been discharged for a long time from a recording head, the ink in discharge ports sometimes evaporates and dries, and the discharge ports are plugged up. Consequently, bad discharging, such as unstable discharging, undischarged states or the like, is sometimes caused. The capping means caps (closes up tightly) the discharge port surface of a recording head during the time when recording is not performed to reduce or to prevent the increase in viscosity or the fixing of ink owing to the evaporation and the drying of the ink in the discharge ports of the recording head. Moreover, when air bubbles intrude into the recording head, or when the ink discharge ports are clogged owing to the increase in viscosity or the fixing of the ink attached to the ink discharge port surface to dry, the suction means produces a negative pressure in the cap with a suction pump communicating with the cap in the state in which the discharge port surface of the recording head is shut tightly with the cap. Thereby, the suction means exhausts the ink discharge ports and exchanges the ink in the ink discharge ports with fresh ink to maintain and to recover normal ink discharging.
As the configuration of the wiping means, the configuration of performing wiping and cleaning with a wiper made of a rubber-like elastic member moving in the arrangement direction of the ink discharge ports of the recording head is frequently adopted. Moreover, from the point of view of preventing the increase of the width of a recording apparatus, the cap and the wiper are configured so as to overlap each other, so that the wiper passes between the cap and the discharge port surface when the cap is separated from the discharge port surface. Moreover, as one of the driving methods of the cap, the method of making the cap approach or recede against or away from the discharge port surface by means of a lever or the like, which is driven to rotate with a cam member for cap control, is adopted. Moreover, as one of the driving methods of the wiper, the method of moving the wiper in rectilinear reciprocating directions (for example, forward and reverse directions) with a cam, a rack and pinion, a lead screw, or the like is adopted. Thus, the wiper is configured to pass between the cap and the discharge port surface when the cap is separated from the discharge port surface. In this case, the wiper is frequently moved from an upstream side to a downstream side along a discharge port train while the wiper is made to slide to rub the discharge port surface to wipe the discharge port surface to clean it.
However, in the recovery mechanism portion including the wiping means of the system of driving the wiper with the cam, the rack and pinion, or a mechanism formed by combining them, a larger cam member or a longer rack member becomes necessary as the movement distance of the wiper becomes longer owing to the increase of the area of the discharge port surface. Consequently, the apparatus body becomes larger, which in turn makes it difficult to implement the miniaturization of the recording apparatus. Moreover, in the recovery mechanism portion including the wiping means of the system of driving the wiper by the use of the lead screw, it becomes necessary to form an approach section of a predetermined distance from a starting position of the operation of the wiper lest the wiper should overlap the cap until the cap is sufficiently separated from the discharge port surface.
However, if the approach section is formed to be sufficiently long, the size of the recording apparatus body in the front-to-rear direction increases to make it difficult to miniaturize the recovery mechanism portion or the recording apparatus. Even if the pitch of the lead screw in the approach section is changed, the wiper moves within the approach section. Consequently, the size of the recording apparatus body in the front-to-rear direction becomes larger by the movement distance.